What is the greatest common factor of 40, 50 and 70?

To find the greatest common factor (GCF) of 40, 50, and 70, follow these steps:

1. First, find the prime factors of each number.

   • The prime factors of 40 are 2, 2, 2, 5 (2^3 * 5)
   • The prime factors of 50 are 2, 5, 5 (2 * 5^2)
   • The prime factors of 70 are 2, 5, 7 (2 * 5 * 7)

2. Next, identify the common prime factors.

   • The common prime factors are 2 and 5.

3. The greatest common factor is the product of the lowest power of the common prime factors.

   • The lowest power of 2 common to all three numbers is 2^1.
   • The lowest power of 5 common to all three numbers is 5^1.

4. Multiply these together to get the GCF.

   • So, the GCF is 2^1 * 5^1 = 2 * 5 = 10.

Therefore, the greatest common factor of 40, 50, and 70 is 10.